1. Field of the Invention
The present invention relates to a multivalued subtracter which may apply to various data processings such as image processing or signal processing for communication or a microprocessor.
2. Description of the Related Art
In general, a subtracter is a kind of arithmetic and logic unit and is a dedicated circuit for subtraction.
In recent days, computer-equipped instruments containing logic operating units such as a microprocessor are used in society. These computer-equipped instruments include a personal computer, a point of sales (POS) terminal and a cash register. In such instruments, a subtracter is built-in for executing various logic operations, and the operating performance of the subtracter is likely to increase through the effect of various methods.
The subtracter known by the inventors of the present application, however, provides more operating gate stages as the processing of bit signals becomes faster and faster. More operating gate states result in delaying a signal by a greater amount, thereby making the subtraction unstable. The known subtracter has such a disadvantage.
Furthermore, the known instruments based on binary electronics are requested to have faster and more highly functional electronic components as the amount of data to be processed is made larger and larger. The binary electronics technique, however, provides limited information processing capability. Hence, the technique cannot cope with a quantity of data larger than a certain level. This means that the operating capability given by the binary electronics technique cannot achieve the capability which is now being requested. This is another disadvantage.